As long as a woman is covering herself in accordance with the instructions of Quran, there is no harm in swimming.
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Discussion 112902
Such ahadith apply to scenarios where there is unsafe environment for women and no privacy is available. Women were discouraged to expose themselves in such unsafe environments. This is said as a precautionary measure. So if a certain place provides complete privacy to women without any risk of exposure to others, whether men or women, then there is no harm in using that place. The context of the Hadith also tells us that Ayesha (rta) narrated this Hadith to women who used to go to public bathhouses where privacy was minimal to none.
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Swimming For Women - Ask Ghamidi
Assalamu Alaikum, there are some people who believe that women can not go swimming due to Hadith of Sunan Ibn Majah 3750 which says (not exact words) that